Copying the UK format of increasing the prize money as contestants progress through 15 multiple choice questions, the show attracted a US TV summer high of 10 million viewers with its first screening on 16 August.

The ABC quiz now boasts some 16 million viewers, with the competition reaching its climax on 30 August.

The show has just crowned its first half-millionaire, lawyer Michael Shutterly. All that stood between the 46-year-old and a shot at US TV's richest ever prize was a poser about rock group Jethro Tull.

Tarrant lauded as quiz master

Having answered 14 questions correctly, including identifying Albino Luciani as Pope John Paul I, Shutterly played safe and bowed out of the competition.

So far no other version of the show, screened in five countries, has been so close to awarding the top prize.

Although the programme is still not as popular as the UK version, hosted by Chris Tarrant - which was watched by 19 million at its height - ABC has vowed to bring the show back next year.

The success of the quiz, hosted by American TV regular Regis Philbin, has revived interest in the game show. Tried and tested UK series are now being targeted by US networks.

Game shows 'respectable again'

"We sent a bottle of champagne with a note saying 'Thanks for making game shows respectable again'," said Scott Stone, boss at rival Stone Stanley Productions.

"That was my idea." Reeves show goes American

His company is working on a version of the BBC's Reeves and Mortimer panel show, Shooting Stars.

"I'm having the hottest sales season I've ever had," boasts Ben Silverman from the William Morris agency, who packages international shows for US networks.

William Morris is set to buy the BBC comedy quizzes They Think It's All Over and It's Only TV But I Like It. The agency is also scouting for show formats from the likes of Granada, LWT and Carlton.

"It's a short cut for buyers in evaluating these shows when they can see a finished episode," says Silverman.

ABC, the network riding high after the success of Millionaire, is set to screen a version of the BBC satirical show, Have I Got News For You.

Whether all these shows will prove as popular as the nail-biting Millionaire is a gamble.